首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1861篇
  免费   170篇
  国内免费   20篇
耳鼻咽喉   9篇
儿科学   100篇
妇产科学   7篇
基础医学   230篇
口腔科学   77篇
临床医学   248篇
内科学   334篇
皮肤病学   56篇
神经病学   132篇
特种医学   257篇
外科学   202篇
综合类   50篇
预防医学   130篇
眼科学   25篇
药学   103篇
  1篇
中国医学   1篇
肿瘤学   89篇
  2023年   11篇
  2022年   8篇
  2021年   21篇
  2020年   20篇
  2019年   21篇
  2018年   32篇
  2017年   20篇
  2016年   38篇
  2015年   44篇
  2014年   34篇
  2013年   64篇
  2012年   51篇
  2011年   53篇
  2010年   73篇
  2009年   70篇
  2008年   49篇
  2007年   57篇
  2006年   61篇
  2005年   47篇
  2004年   50篇
  2003年   64篇
  2002年   48篇
  2001年   36篇
  2000年   23篇
  1999年   43篇
  1998年   97篇
  1997年   82篇
  1996年   65篇
  1995年   58篇
  1994年   46篇
  1993年   52篇
  1992年   27篇
  1991年   45篇
  1990年   32篇
  1989年   68篇
  1988年   62篇
  1987年   54篇
  1986年   35篇
  1985年   43篇
  1984年   22篇
  1983年   32篇
  1982年   20篇
  1981年   18篇
  1980年   26篇
  1979年   12篇
  1978年   17篇
  1977年   16篇
  1976年   15篇
  1975年   17篇
  1969年   7篇
排序方式: 共有2051条查询结果,搜索用时 0 毫秒
11.
12.
13.
A lump on the midface of a child can pose as a diagnostic dilemma. There is a wide variety of possible differential diagnoses, ranging from simple benign conditions such as a sebaceous cyst, dermoid cyst, lipoma, neuroma and neurofibroma, to potentially devastating conditions such as odontogenic myxoma.A case of a child in which the formulation of a definite diagnosis was clinically and histologically challenging is presented.  相似文献   
14.
15.
16.
17.
18.
BACKGROUND: Acquired cerebriform intradermal naevus (CIN) is a rare form of pseudo cutis verticis gyrata. CASE REPORT: A case of acquired CIN of the scalp in a 46-year-old male patient is presented. The clinical and histopathological presentations of CIN are described and the therapeutic possibilities are discussed. CONCLUSIONS: In each individual case the physician must decide whether to do surgery or follow a wait-and-see policy. There is little risk of malignant change of CIN, and surgical excision of such lesions often involves evident mutilation.  相似文献   
19.
Objective: Right upper lobe collapse is a common radiographic finding in intubated children. We hypothesized that deep suctioning and uncontrolled negative pressures during endotracheal tube suctioning were significant contributory factors. Methods : The incidence of right upper lobe (RUL) collapse in intubated, ventilated children on a paediatric cardiac intensive care unit was determined over a 3-month period ( n = 102). Graduated suction catheters and suction vacuums of < 165 cm H2O were then introduced. Another prospective audit was carried out 3 months later ( n = 60). Results : We found that 24% developed RUL collapse and 4 developed an apical pneumothorax. Following the introduction of graduated catheters and controlled vacuums pressures, a significant reduction in the incidence of RUL collapse, to 7%, was observed ( p < 0.05). Conclusions : We conclude that high negative pressure and deep-suctioning causes RUL collapse in children. Any lobar collapse not only prolongs the child's stay in intensive care, but can be associated with further morbidity which may have a serious implication. By improving suctioning technique this morbidity can be significantly reduced.  相似文献   
20.
Recombination of deltaRec to psiJalpha will delete the TCR delta gene, which is thought to play an important role in the bifurcation of the TCR alphabeta versus TCR gammadelta differentiation lineages. We recently detected a DNA-binding protein in human thymocytes, the so- called PJA-BP, which recognizes the psiJalpha gene segment and might be one of the factors involved in the regulation of preferential deltaRec- psiJalpha rearrangements. We now investigate PJA-BP expression and its correlation with TCR delta gene deletion in thymocytes. Our electrophoretic mobility shift assay experiments showed that the PJA-BP is evolutionary conserved in human, murine and simian thymocytes. Using a large series of human hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is thymocyte specific and seems to be restricted to thymocytes committed to the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte subpopulations showed that preferential deltaRec-psiJalpha rearrangements as well as PJA-BP expression can be detected from the immature CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage onwards. These experiments indicate that expression of PJA-BP in human thymocytes starts simultaneously with preferential deltaRec-psiJalpha rearrangements, which supports our hypothesis that PJA-BP is one of the factors involved in the preferential recombination of deltaRec to psiJalpha.   相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号